The present invention relates to a planetary gear system comprising a primary shaft, a propeller shaft, at least one intermediate shaft, a planet wheel support provided on at least one of said shafts, and at least two planet wheel journals on said planet wheel support.
It is previously known to provide planetary gears with a number of intermediate shafts so that the total gear ratio is achieved in two or more steps. Each intermediate shaft is thereby suitably provided with a planet wheel support with a number of planet wheel journals on which planet wheels are mounted, and a sun wheel. The planet wheels thereby co-operate with a sun wheel provided on an adjacent shaft, and the sun wheel co-operates with planet wheels provided on another adjacent shaft. By using two or more gear steps great total gear ratios can be achieved, but this is achieved at the cost of a comparatively long axial extension of the planetary gear system. Each intermediate shaft must, as well as the primary shaft and the propeller shaft, be provided with bearing and centering means, which together with the planet wheel supports and the sun wheels contribute to increase the necessary axial extension of the system. Another difficulty with multiple step gears is that possible gear plays can be added to an annoyingly great total play with running problems and noise troubles as a consequence.